Mine signal plant



Jan. 11 1927. 14,257

F. SCHEFFLER MINE) SIGNAL PLANT Filed April 11, 1925 2 Sheets-Sheet 1 I I 95 g;

(WW/VI Jan. 11 1927.

F. SCHEFFLER MINE SIGNAL PLANT 2 Sheets-Sheet 2 30 36 8c life {[4 J1) 81' xi Filed April 11, 1925 Patented Jan. 11, 1927.-

FRITZ SCHEFFLER, OI KIEL, GERMANY.

PATENT OFFICE.

MINE SIGNAL PLANT.

Application med April 11, 1925. Serial No. 22,428, and in Germany March 19, 1924.

The invention refers to mine signal plants. Such plants serve for controlling the hoisting operations in mines. Signals are at present usually transmitted by acoustic signals from one of the levels to the pit-mouth indicating the hoisting direction; simultaneously it is observed optically in the engine-room. The level signal is then passed on from the pit-mouth to the engine room acoustically as order signal. The engineer can first of all compare the order signal given hinfacoustically with the visible signal from the level at the pit-mouth and, if both signals agree, carry out the order.

The invention takes into consideration, that when comparing the acoustic, for instance a bell, order signal with the level signal shown optically, mistakes may easily occur. Comparison .of an optical with an acoustic signal needs thought which again requires a certain degree of attention.

The invention has the purpose of eliminating the process of thinking and thus of removing a source of error easily leading to the loss of lives. According to the invention the signals transmitted from the levels to the pit-mouth and also the order signals from the pit-mouth to the engine room are, for this purpose, placed optically so close to one another, that differences in the same become quite apparentto the observer. In this arrangement the engineer must read his order signal, As the comparison signal is made visible quite close to the order signaLthe engineer is involuntarily obliged to compare both groups of signals with one another.

In signal systems of this character used heretofore the signals cannot be easily compared in the novel manner pointed out above because the spaces between the groups of signals are generally not uniform. My invention provides means for keeping these spaces uniform even when the intervals at which the signals are given, are not exactly uniform. The signals arriving from the levels at the pit-mouth in the hoisting engine-room are mostly represented by a row of individual light (lots or the like in a certain order. For this purpose the order signals transmitted from the pit-mouth to the engine-room are placed below or above the aforementioned row in such a manner, that corresponding signal characters are placed as much as possible immediately above one another.

. My invention is illustrated in the accompanying drawings in which- Fig. 1 represents a signal reception box,

Fig. 2 represents a signal transmission system partly shown diagrammatically, partly in actual construction in longitudinal vertical section, v

Fig. 3 represents a portion of the signal reception box mechanism in transverse vertical section, and

Fig. 4.- represents the entire signaling system applied to a mine,

Such a construction is, for instance shown in Fig. 1 of the drawing. a is a cast-iron casing fastened to a foot 5, the former having on its front side two openings 0 and b arranged close above one another. Within these openings, double-cross-hatched in the drawing, the signal characters appear as small white fields. In the one row, for instance the upper one, the signals transmitted from the levels to the pit-mouth appear, and in the lower. one the order signals, transmitted from the pit-mouth to the engineroom. The signal shown in the example would be transmitted acoustically by two strokes, interval, three strokes, interval, two strokes. It is quite clear on viewing the drawing, that for instance the appearance of one dot more or less in the lower row would disturb the total impression of the picture composed of the two rows of characters so much, that this irregularity could not easily be overlooked by the engineer. It is obvious, that both rows of characters can the more easily be compared the closer they are to one another, i. e. the narrower the ridge f remaining between the two openings 0 and (Z is made. This ridge f can be omitted completely, so that the two rows of characters almost touch one another. A correct signal would then only contain light vertical dashes double as long as the individual dashes or characters 6. An incorrect signal would immediately be noted, as one or more of these dashes would be only half as long.

Besides the optical signal which is transmitted from the pit-mouth to the engineroom, the customary acoustic, individual signal may remain. It, however, seems more advantageous to omit the acoustic si al and replace it by an ordinary genera alarm, which merely draws the engineers attention to the fact, that an order signal is being given. The engineer is thus called upon to concentrate his attention only to the optical indicator and on this occasion to compare both rows of signals with one another.

In what manner the individual signal elements e are brought into the indicator fields c and d is of 'no account so far as the present invention is concerned. It is, however, important that the respective individual elements, correspondingly located in the two rows, should, it possible, be exactl in vertical alinement. Consequently on y under certain conditions is it advisable to employ an arrangement heretofore frequentl used in which out of a row of bars suspen ed adjacent to each other, certain bars are brought into the indicating field by means of a hammer moved regularly during the delivery of signals. In this arrangement the spaces between the groups of bars brought individually into the indicator field are of different lengths, according to the length of the interval between the strokes given by the operator. As, however, the level signals and the order signals are given by different persons, considerable differences may appear, which may possibly even frustrate the result sought.

In Figs. 2 and 3 the construction of a signal system is shown, in which, according to the invention, each signal character or element is represented by a single indicator end the space between several groups of signals composed of these elements is attained by the absence between each group of the same number of signal elements within the row of elements for instance as shown in Fig. 1, one element omitted between all adjacent roups, which element constitutes the uniorm signal spacing in both rows.

To make the connection with the contrivances appertaining to the system clear, only one row of signal elements is shown in Fig. 2. For the second row of elements the same circuit connections are necessary as will appear from Fig. 4. The arrangement of both rows of signal elements relatively to each other is represented in Fig. 3, in which both rows of elements 6 are seen endwise. The row composed of the signal elements 35 is, as shown in Fig. 3, arranged behind the second row composed of the signal elements 6. The front row of elements e in the raised position is covered by a plate 9 and the back row 35 by a plate h. In Fig. 3 an element e belonging to the upper row (Fig. 1) and an element 35 belonging to the lower row (Fig. 1) are visible to the operator. The element 35 here rests directly on a ridge 34:, whilst the element e is supported on the same ridge 34 by a thing interposed rod 71 visible as little as possible.

In the working system for the signal elements 35, Fig. 2, conductors 1 and 2 are connected to a current source. The conductor 2. for instance, is led from the engine room of a mine hoistin engine into the it to the lowest level. t each level a pul key 3 is connected to the conductor 2; for clearness sake only one key is represented in the drawing. All other level-keys which may be provided in the system are connected in parallel to the pull-key 3 shown. With this ullkey 3 a circuit can be closed leading rom the conductor 2 over the pull-key 3, a solenold coil 4, a circular contact rail 5, a contact bridge 6, one of the circularly arranged contacts 7, 7 b and one of the relay coils 8". 8 S oi the signal box, connected with that contact, and thence thru a return lead common to all relays to conductor 1. The contacts 7 are connected to the respective relay CullS 8 in such a manner, that the contact 7 is in connection with the relay coil 8, the contact 7 with the relay coil 8", etc. The contact bridge 6 is fastened to an arm 9 which is carried by pivotal shaft 10 so that it can rotate thereon. A ratchet wheel 11 is fixed to arm 9, and a pawl 12 engages wheel 11 by its weight. A spiral spring 13 tends to return the contact arm 9 into its normal position, i. e., on to the contact 7. Pawl 12 is pivotally attached to bell crank lever 14, the latter being pivotally supported on shaft 10. By means of a strap 15 an armature 16 is linked to the other arm of bell crank 14, this armature being kept in the position shown by a spring 17. It is lowcred against the tension of this spring by I energizing coil 4. The path of the armature 16 is such, that ratchet wheel 11 is fed two teeth by it during one complete stroke. The number of teeth of ratchet wheel 11 within a given angle is the same as the number of contacts 7 included within a similar angle. Consequently the contact bridge 6 is switched over two contacts 7 during a complete stroke of the armature 16. The armature 16 is extended downwards in the form of a rod 18. A stop 19 is fixed to this rod limiting the throw of the armature 16 in upward direction. Besides, a second armature 20 is carried by rod 18, which is longitudinally movable on the rod. This armature rests with an extension 21 against the stop 19. The armature 20 is under the influcnce of the magnet coil 22. The size of the coil 22 and the armature 20 is such, that the magnetic pull does not suffice to start a downward motion against spring 17 independently, but sufiices to balance the tension of the spring 17, if the armature 20 is seated with its cone shaped end on the correspondingly shaped fixed pole of the magnet casing. The stroke of the armature 20, until it rests on the fixed pole surface of the coil, is only half the stroke of the armature 16. The coil 22 is connected with its one terminal to the conductor 2 and with the other terminal over a contact 23 to the conductor 1. The contact bridge of the contact 23 is fixed to a. lever 25,

on which the armature 16 rests, the lever be-.

ing pivotally supported at the point 24. The lever 25 is held in the normal position shown by a spring 26. To the end of lever 25 the piston of a dash pot 27 is pivotally attached. This dash pot is controlled by a check valve 28 at its upper end. which opens at the downward motion of the piston, but during the upward motion almost closes except for the adjustable leakage customar in such devices, not shown here in etail. Consequently the downward motion of the piston can take place almost without obstruction, whilst the speed at the u ward motion is regulated b a suitable adjustment of the leakage of t 1e valve 28. The stationary contacts of switch 23 are constructed yieldingly so that they do not form a positive stop on the downward motion of the lever 25. The pawl 12 has an arm 29. In this arm 29 a rod 30 is disposed which is linked to an armature 31. By energizing coil 32, which can be connected in circuit over a contact lever 33, the armature 31 can be raised. At its upper end the armature 31 carries a ridge 34 pre viously mentioned as carrying signal elements 0 and 35. This ridge serves to bring these signal elements, after they have dropped into the indicator fields back into engagement with the catches 36, which hold these elements in their upper invisible position. The dotted lines 37 show the height of the indicator fields within which the elements 35 become visible.

It may be mentioned that the arrangement described above is meant to serve for transmitting signals, which are given with one of the usual signal installation from the level to the pit-mouth, simultaneously optically to the engine-room, so that the hoisting engineer is in the posit-ion to compare the order signal given later acoustically from the pit-mouth with that given from the level to the engine-room and made visible according to the present invention. In order not to unnecessarily overload the drawing, the customary well known arrangement of the acoustic signals has been omitted from Fig. 2. Suppose the lever 33 to be the brakelever of the hoisting machine, whilst the pull-key 3 be arranged at any of the several levels. The remainder of the arrangement shown in Fig. 2 would best be disposed in a casing and he installed in the hoisting engine room.

Let us suppose that the contact bridge 6 stands on the first contact 7 and all annunciators 35 are raised and suspended by their respective catches 36. If now, for instance, with the level kev 3 the signal i. e., one bell-stroke, interval, two bell-strokes is transmitted to the pit-mouth, then the following occurs simultaneously in the device shown in Fig. 2.

In the first closing of contact 3 a circuit is closed over this contact, the magnet coil 4, contact rail 5, the contact bridge 6, the contact 7 a and the relays coil 8 appertaining to same. The relay 8 attract the arm of the catch 36 and thereby releases the tablet or signal element 35, so that it becomes visible in the lower indicator field. Besides the armature 16 is lowered against the tension of the springs 17 and 26 to its lowest position and thus pawl 12 glides over two teeth to the left on ratchet wheel 11. Simultaneously with the armature 16, armature 20 drops through half the distance of the path of armature 16, and comes to rest on the hollow cone pole surface of the magnet casing surrounding it. In its downward motion the armature 16 simultaneously takes the lever 25 with it, so that the contact 23 is closed and the field coil 22 is energized. The coil 22 now holds the armature 20 in its lowest position until the contact 23 is released. As soon as the key 3 is again opened, the armature l6 tries to return to its original position under the influence of spring 17. It can return halfway unchecked and thus advance ratchet wheel 11 one tooth to the right thereby advancing the contact bridge 6 to the contact 7". After having returned half-way the stop 19 strikes the extension 21 of the still attracted armature 20, so that the armature 16 for the moment mains in this position. however. the lever 25 has started its return path under the influence of the spring 26. The return motion of the lever 25 is retarded by dash pot 27: during the first part of this return motion the contact 23 still remains closed and during this time the armature 16 is still detained on the half return path by the armature 20. If now, within this period of time of about second a new closing of the circuit by the signal key 3 does not occur, relay 8 is not energized and I thus its signal element 35 remains suspended and out of the indicator field, as shown in Fig. 2. Further the contact 23 is opened and the magnet coil 22 becomes deenergized and releases its armature 20. Consequently this armature ceases to serve as a stop for armature 16 and the latter now returns to its original normal position under the influence of the spring 17 and hereby advances ratchet wheel 11 one tooth further to the right. Qonseouently the signal ele ment 35 is omitted from the field and the contact bridge 6 is switched from the contact 7 to the contact 7.

It the key 3 is now closed. relay 8. being then located within the key circuit is excited and causes signal element 35 to drop. Simultaneously the armature 16 and the other parts of the mechanism acting together with it are set in motion again as explained before. If now the third signal imre-- Simultaneously,

pulse is given by the operator at key 3 very quickly after the second impulse which brought element 35 into the field, the time controlled by dash pot 27 has, in this case, not sufiiced for the contact 23 to be opened by the spring 26. The third signal current is therefore acting at the moment, when the armature 16 has only completed half of its return path and consequently the contact bridge 6 has only been advanced one contact further to the contact 7. If during this time, as already mentioned above, the third closure of the key 3 takes place, the element 35 immediately adjacent to element 35 is caused to drop by actuating relay 8, and the armature 16 is only drawn half a stroke downwards, so that the pawl 12 is drawn back also only one tooth on ratchet wheel 11. If no further signal impulse follows, the armature 16 makes its full return path with the interval provided by the means described and hereby switches the contact bridge 6 two contacts further on.

The same signal is simultaneously given acoustically to the pitanouth by means not shown here. As soon as the banks man at the pit-mouth transmits this order signal to the engineer, the engineer can immediately assure himself that the order signal from the pit-mouth coincide with that transmitted from the level to the pit-mouth. He will, as soon as he is certain that they coincide, release the brake lever of the hoisting engine. He thereby closes the contact 33 on the brake-lever and switches the magnet coil 32 into the circuit. Consequently its armature 31 is raised and with it the fallen signal elements 35, 35 and 35 are again returned to their normal raised position by the ledge 34. At the same time the arm 29 of the pawl 12 is raised by the rod 29 whereby pawl 12 is disengaged from ratchet wheel 11, so that the latter is able to return to its normal position under the in fluence of the spring 15, in which the contact bridge 6 again connects the contact rail 5 with the contact 7. The system is now ready for a new signal.

Fig. 4 shows the manner in which an arrangement according to the invention previously described can be fitted into an or dinary mine signal system.

It will be noted from this figure that the entire system is principally divided into two circuit systems of which the first circuit makes signal communication between the levels and the pit-mouth possible. while the second serves for the transmission of signals from the pit-mouth to the engine room. The fist named circuit system is arranged as follows:

From the positive lead of any current source a lead, runs into the pit and is there connected to the levers of the signal keys 3, 3, 3", 3 at the different levels. A

second lead running into the pit is in connection with the stationary contacts of these signalling keys and returns from the pit over the alarms B, arranged at the difierent levels and at the pit-mouth, to thecoil 4. From this coil 4 the flow of the current is as described in Fig. 2, viz, over the contact rail 5, the contact bridge 6, one of the. contacts 7, one of the relay coils 8 to the negative le of the current source. UsuallIy two skips are employed in mine hoisting. f one is at rest at the pit-mouth, the other is at one of the levels. As soon as the attendant at the level has his skip ready for hoisting he gives with his signal lever, for example, 3', the signal hoist, which may consist of 2 strokesa pause-one stroke. By working the signal key he closes the above mentioned circuit leadin over the signal alarm B and the optical indicator at the it-mouth. Consequently the alarms at all evels and at the pit-mouth ring the given sign. The man giving the signal is hereby first of all informed that his signal has passed thru. Besides this the other levels are aware that hoisting begins. F inally the banks man at the pit-mouth has received the report of readiness from the level. Moreover the optical apparatus in the engine room has caused the first, second and fourth signal element in the lower indicator row to drop into the lower field, according to the manner of operation already described. As soon as the banks man at the pitmouth also has his skip ready, he gives the same signal to the engine room with the signal-key K. The signal-key K lies in a current loop leading from the negative lead to the fixed contact of the signal-key, over the si nal-key K itself, the alarm Bp arrange at the pit-mouth, the alarm Be fitted in the engine room and that portion of the optical apparatus marked E. This portion also corresponds exactly in its arrangement to Fig. 2, only with the difference, that a second row of relays 8 for the upper row of drop indicators is worked by it. \Vhen the signal is given, the banksman at the pit-mouth first of all hears by means of the alarm Bp, that the level signal has really passed thru. Besides this the engineer hears, by means of the alarm Be, the signal to be carried out by him. As the first, second and fourth drop-indicators of the upper signal row are now brought into the upper field by the apparatus portion E of the optical signal arrangement when the banks-man operates key K, the engineer is now assumed by glancing at the optical apparatus that the signal for the particular hoisting operation given from the pit-mouth coincides with the signal given from the level to the pit-mouth. He will then observe a picture such as appears from Fig. 1 where the two fields show the coinciding signals:

two strokesause-three strokespausetwo strokes. brake-lever 33. He there y brings into action the signal restoring coil 32, described with reference to Fig. 2, which now removes all dropped signal elements from the field. The signal system is now prepared for a new signal.

The signal key 3 at the it-mouth shown in Fig. 4 is not absolute y necessary for working. It is, however, generally rovided so as to enable the banks-man to emand a re etition of a misunderstood signal from the evel. Such requests for repetition would also appear at the indicator in the hoisting room in the field in which the level signals appear and thus give him notice that a misunderstanding exlsts.

Having now particularly described the nature of my invention and in what manner the same is to be performed, I declare that what I claim is 1. In a mine hoist signal system for transmitting orders from the various levels to .the pit-mouth and hoist control room, the combination of a signal receiving device at said control room, comprising a signal field and two lfke sets of signals disposed in said device, means mounting said sets of signals for movement into said field one immediately above and in vertical registry with the other, a signal receiving device at said pitmouth, means at each level for simultaneously operating the signal at the pit-mouth and for moving selected signals of one of the said sets of signals at said control room into the signal field, and means at said pitmouth for moving selected signals of said other set of signals at said control room into the signal field, whereby the two sets of signals may be readily compared.

2. In a mine hoist signal system for transmitting orders from the various levels to the pit-mouth and hoist control room the comination of a signal receiving devlce at said control room comprising two sets of individualsignal characters from each of which set a signal may be composed, and a signal field for each set, means mountin each set for movement into its, field, the signal field of one set being disposed immediately above the field of the other set to register in a vertical line corresponding si nal characters of one set with those of t e other set, means for consecutively movin the desired characters of each set individua ly into their pertaining field, said means comprising an operating relay for each signal character and its associated circuits and a character releasing element actuated when said relay is energized, a step switch having contacts for setting said relay circuits and having means for closing said contacts in consecutive contact steps a solenoid having an ar mature for operating said switch and an ow the en 'neer releases the operating key in circuit with said solenoid and with the energizing circuit set by said switch for closing the particular relay circuit set, said armature having suflicient throw to advance said switch two contact steps, means for arresting the movement of said armature for a )redetermined t me interval after it has a vanced the switch one contact step to permit sufficient time to close said key to energize, if desired, the relay connected by said first contact step, and means for releasing the arrested armature to permit it to complete its throw to advance the switch the second contact step after said time interval, if said key has not been closed during said time interval.

3. In a mine hoist signal system for transmitting orders from the various levels to the pit-mouth and hoist control room, the combination of a signal receiving device at said control room comprising two sets of individual signal characters from each of which set a signal may be composed, and a signal field for each set, means mounting each set for movement into its field, the signal field of one set being disposed immediately above the field of the other set to register in a vertical line corresponding signal characters of one set with those of the other set, means for consecutively moving the desired characters of each set individually into their pertaining field, said means comprising an operating relay for each signal character and its associated circuits and a character releasing element actuated when said relay is energized, a step switch having contacts for setting said relay circuits and having means for closing said contacts in consecutive contact steps, a solenoid having an armature for operating said switch and an operating key in circuit with said solenoid and with the energizing circuit set by said switch for closing the particular relay circuit set, said armature having sufiicient throw to advance said switch two contact steps, means for arresting the movement of said armature for a redeterminedtime in terval after it has a vanced the switch one contact step, to permit sufficient time to close saidkey to energize if desired the relay connected by said first contact step, said arresting means comprising a holding solenoid and a separate energizing circuit therefor containing a time switch tending to open and being mechanically connected to and closed by the armature of the first solenoid when energized, said holding solenoid having an armature disposed in the operating III the latter. to open for a predetermined time interval, said holding solenoid being deenergized when the time switch opens after said time interval and perm tting the armature of the first solenoid to complete the second half of its return throw, thereby moving the step switch the second step and connecting the succeeding relay into energizing connection, if said key has not been closed dur ing said interval.

4. In a mine hoist signal system for transmitting orders from the various levels to the pit-mouth and hoist control room, the combination of a signal receiving device at said control room, comprising a signal field and two sets of signals, means mounting said sets of signals for movement into said field one immediately adjacent the other, a signal receiving device at said pit-mouth, means at each level for simultaneously operating the signal at the pit-mouth and for moving selected signals of one of the said sets of signals at said control room' into the signal field, and means at said pit-mouth for moving selected signals of sa:d other set of signals at said control room into the s gnal field, whereby the corresponding individual signal elements and the spaces between them in both sets relatively occupy the same positions in their respective fields and whereby the two sets of s gnals may be readily compared.

In testimony whereof I affix m signature.

FRITZ SGHLFFLER. 

